I have a Ferroli combi boiler which has worked fine for the last 8 years. However it has recently begun to give me a problem. The pressure builds up slowly whilst it's running to bar 4. Each day I bleed off enough water to reduce the system pressure to 1 bar, but by the end of every day I need to bleed off more water to reduce the pressure. I am constantly taking water out of a 'closed system' which by definition is impossible... Can anyone help with this?

Peter Naylor, December 2007

Whilst all answers are valid Baz is probably the most on the money IMHO.
Sounds to me like the expansion vessel is totalled. Had 2 like this recently

LogicAl, February 2008

Whilst all answers are valid Baz is probably the most on the money IMHO.
Sounds to me like the expansion vessel is totalled. Had 2 like this recently

LogicAl, February 2008

Whilst all answers are valid Baz is probably the most on the money IMHO.
Sounds to me like the expansion vessel is totalled. Had 2 like this recently

LogicAl, February 2008

I had the same problem myself recently.The filling loop should be disconnected & if the pressure still rises try closing the cold water main entering the boiler .If this stops the rise in pressure you probably have a heat exchanger which is corroding & is allowing mains water to enter the heating circuit through a pinhole in the exchanger

colin, January 2008

Your filling loop is passing

George Anderson, December 2007

as the other person said, could be the expansion vessel, potentially could be the filling connection if its left connected but dont think it would get to 4 bar! best get someone in to check it out

kev!, December 2007

it could be your expansion tank

baz, December 2007